a phrase uttered in encouragement meaning: "muster your courage, intestinal fortitude and love for the American-way in preparation for an upcoming (or admist a) challenge
of epic proportions!"
(uttered many times by one of the dudes in the movie "The Matrixs:Revolutions" during battle
against the electro-mechanical foe)

An action akin to the high-five or the handshake. The act of touching fists knukle-to-knuckle in greeting or departure. In 2003 this action was accompanied by the phrase "knuckle-up" but has since just become the motion without the phrase. The first instance of this action and phrase was in Dallas, TX in the mid-90's and has since become a common gesture in most public forms of transit in NYC.

Jimbo-- "Is that some kind of a gang sign?"
Miguel--"Nah, that's a knuckle-up, bro."